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# Equations for time and rate problems and their solutions

52. How can a graph be used to determine how many solutions an equation has?

8. Bobbi picks 1 qt in 20 minutes. Blanche picks 1 qt in 25 minutes. How long would it take them to pick one quart if they work together?

14. The speed of a freight train is 15 mph slower than the speed of a passenger train. The freight train travels 390 miles in the same time that it takes the passenger train to travel 480 miles. Find the speed of each train.

44. It takes 60 oz. of grass seed to seed 3000 ft ^2 of lawn. At this rate, how much would be needed to seed 5000 ft^2 of lawn?

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#### Solution Preview

Please see the attached file (boxes) for answers.

52. How can a graph be used to determine how many solutions an equation has?

Plot y against x. The values of x at which the plot cuts the x axis are the solutions. The number of points at which the x axis is crossed is the number of solutions.

8. Bobbi picks 1 qt in 20 minutes. Blanche picks 1 qt in 25 minutes. How long would it take them to pick one quart if they work together?

Let the rate at which Bobbi works = x qt/min
Let the rate at which Blanche works = y qt/min
Combined rate = x + y qt/min
Time taken to ...

#### Solution Summary

Sets up equations for time and rate problems and solves them.

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